1. Field of the Invention
The present invention relates to an editing device for editing an HDTV (high-definition television) signal by using a computer and to an editing apparatus and an editing method, both of which using a computer, for an HDTV signal.
2. Description of the Related Art
At video-content production departments such as radio stations and post production facilities, content, such as TV programs, commercials, or movies, is commonly produced by editing material, for example, video data and audio data, with nonlinear editors.
As the nonlinear editors, computers (workstations and personal computers) on which editing application software is installed have been conventionally used.
With such a nonlinear editor, material of a desired scene or the like is transferred from, for example, a VTR (video tape recorder) or a video camera, in which material is recorded, and is stored in a storage device connected to a computer or a hard disk built into the computer.
A computer having such editing application software performs edit processing, such as applying a special effect to the loaded/stored material and combining or connecting one piece of material with another to thereby produce video content (e.g., Japanese Unexamined Patent Application Publication No., 2003-37806 (paragraph Nos. 0024 to 0033 and FIGS. 1 and 2)).
Examples of available computer-based nonlinear editors include a device in which a dedicated PCI (peripheral component interconnect) card for performing edit processing (e.g., special effect processing and combining processing) is installed in a PCI slot and loaded/stored material is transferred to the PCI card via the PCI bus so as to be subjected to edit processing.
In recent years, cases in which HDTV signals are edited have been increasing because of the widespread use of digital broadcasting.
An HDTV signal has fourth to fifth times the amount of information of an SDTV (standard-definition television) signal, and data for one frame of the HDTV signal may amount to about 4 megabytes.
When such an HDTV signal, which has a large amount of data, is to be edited with a nonlinear editor using a computer having a dedicated PCI card, at most, only one piece of HDTV video data can be transferred at a time to the PCI card, because of a limited bandwidth of the PCI bus. Thus, a plurality of pieces of HDTV video data cannot be transferred in parallel.
When one piece of data (material) can only be transferred at a time as described above, the PCI card cannot perform real-time edit processing for combining or connecting one piece of material with another, even a relatively simple edit processing, such as A/B roll editing.
When a computer-based nonlinear editor is configured such that a CPU in the computer renders an image to allow an HDTV signal to be edited, large amounts of CPU power and time are required. Thus, such a nonlinear editor still cannot edit an HDTV signal in real time.
When dedicated large hardware for edit processing is used in conjunction with a computer to perform edit processing, it is possible to edit an HDTV signal in real time. However, the use of such hardware leads to a more expensive and larger editing system.